1. Field of the Invention
The following relates to a system and method for protecting a motor against overuse based on an estimated motor temperature.
2. Background Art
It is increasingly common in automotive vehicles to use electric motors for positioning a wide variety of vehicle components, including specifically both driver and passenger seats. Controllers are typically provided for controlling such motors based on input from a vehicle seat occupant. In that regard, the vehicle seat occupant provides such input by manipulating switches to direct the vehicle seat position. Such switches can include memory position switches, which position the vehicle seat based on position information previously stored in a memory.
Present motors used in automotive vehicles for positioning vehicle seats use a Positive Temperature Coefficient (PTC) device that when heated increases its resistance, thereby protecting the motor against the thermal effects of overuse. However, such a PTC device adds to the cost of the motor assembly.
As a result, there exists a need for a system and method that would eliminate such a PTC device, thereby reducing the cost of the motor assembly. Such a system and method would estimate the motor temperature, based on factors such as ambient temperature, current, time and thermal properties, thereby eliminating the need for thermal protection PTC devices and resulting in a cost savings.